This application claims priority of Taiwan patent Application No. 91204748, filed on Apr. 11, 2002.
1. Field of the Invention
This invention relates to a wood planing machine, more particularly to a wood planing machine with a carriage height adjusting unit driven by a motor.
2. Description of the Related Art
U.S. Pat. No. 5,829,499 discloses a wood planing machine that includes pillars and threaded rods extending upright from a bed, and an upper housing slidably mounted on the pillars and the threaded rods. A transmission gear and a coupling rod are coupled to the threaded rods and the upper housing so as to permit sliding movement of the upper housing along the pillars.
The aforesaid wood planing machine is disadvantageous in that sliding movement of the upper housing is manually operated via a handle. Operation as such is laborious.
Therefore, it is an object of the present invention to provide a wood planing machine with a carriage height adjusting unit that is driven by a motor so as to permit automated adjustment of the height of a cutter carriage of the wood planing machine.
Accordingly, a wood planing machine of this invention comprises: a base having left and right sides; left and right pairs of parallel posts extending upright from the left and right sides of the base, respectively; left and right screw rods extending upright from the left and right sides of the base between the left and right pairs of the posts, respectively, and parallel to the posts; a cutter carriage extending among the posts and having left and right mounting seats that are slidably sleeved on the posts and that have left and right outer walls, respectively, the left outer wall being formed with an opening; a motor mounted on the cutter carriage and having an output shaft that extends outwardly through the opening in the left outer wall; a bracket secured to the left outer wall; and a carriage height adjusting unit.
The carriage height adjusting unit includes: a driving shaft mounted rotatably on the bracket; a sliding member having opposite front and rear ends that are slidably sleeved on the driving shaft so as to permit sliding movement of the silding member along the driving shaft; opposing first and second shaft-driving gears slidably sleeved on and engaging the driving shaft so as to co-rotate with the driving shaft, and mounted on the front and rear ends of the sliding member, respectively, so as to slide with the sliding member along the driving shaft; a driving gear coaxially and securely connected to the output shaft and disposed between the first and second shaft-driving gears; a first gear mechanism operably coupled to the sliding member in such a manner that operation of the first gear mechanism via an external force applied thereto results in sliding movement of the sliding member together with the first and second shaft-driving gears along the driving shaft from a middle position, in which, the driving gear disengages from the first and second shaft-driving gears, to an upward position, in which, the first shaft-driving gear engages the driving gear so as to permit rotation of the driving shaft in a first direction upon actuation of the motor, and from the middle position to a downward position, in which, the second shaft-driving gear engages the driving gear so as to permit rotation of the driving shaft in a second direction that is opposite to the first direction upon actuation of the motor; and a second gear mechanism coupled to the driving shaft and the left and right screw rods so as to permit upward and downward movements of the cutter carriage along the posts upon rotation of the driving shaft in the first and second directions, respectively.